1. Field of the Invention
The present invention relates to heat exchanger coils having spine fin tubing. More particularly, the present invention relates to manufacturing such a heat exchanger.
2. Description of Related Art
Some heat exchangers or coils used for transferring heat from one fluid to another comprise a tube formed into a serpentine shape. Usually a refrigerant, or some other fluid, travels through the interior of the tube, while a second fluid, such as air, passes across the tube""s exterior. To enhance heat transfer between the fluids, the tube may include fins or some other heat transfer member on the exterior of the tube. Often the fins are relatively thin and delicate, thus making it difficult to form the tube into a serpentine shape without damaging the fins. The fins of spine fin tubing, as disclosed in U.S. Pat. Nos. 3,005,253; 3,134,166; 3,160,129; and 3,688,375 (all of which are specifically incorporated by reference herein), are especially fragile and easily damaged.
Currently, serpentine coils with spine fins are manufactured in multiple operations. First, the spine fins are applied to the tube by a machine known as a spine fin wrapper, as disclosed in U.S. Pat. Nos. 4,383,592 and 4,542,568. Later, the tube with the spine fins is transferred to a tube bender, which sequentially makes numerous individual bends until creating the desired serpentine shape.
Typically, each bend is made individually at one general location on the tube bender, while the tube indexes across that general location. To do this, the feeding of the tube into the tube bender must pause momentarily with every bend, which results in a slow, interrupted process.
Moreover, each bend of the tube shifts the completed portion of the coil (i.e., that which has already been formed into a serpentine shape) from one side to the other. This shifting movement can be tolerated if the coil is relatively small. With larger coils, however, attempting to shift the bulk and mass of the completed portion of the coil can damage the spine fins and inhibit the bending process.
Consequently, a need exists for a production piece of equipment that can readily produce large serpentine coils from spine fin tubing.
It is an object of the present invention to create serpentine coils without having to shift the entire coil back and forth with each bend of the coil.
Another object of the invention to provide a multi-operational machine that can apply spine fins to a tube as well as form the tube into a serpentine shape.
Another object is to apply spine fins to a tube while bending the tube at the same time.
Yet another object of the invention is to provide a tube bender that can form serpentine coils of various widths.
A further object of the invention is to form a serpentine coil without having to stop a tube feed roll with every bend of the tube.
A still further object is to provide a tube bender that can simultaneously bend a tube at multiple points.
Another object is to provide a method of creating tight, small radius bends by maintaining the tube in tension.
These and other objects of the present invention, which will better be appreciated when the following description of the preferred embodiment and attached drawing figures are considered, are accomplished in a tube bender that applies spine fins to a tube while simultaneously forming the tube into a serpentine shape.